At present, a touch screen as an input medium is one of simplest, most convenient and natural ways for human-computer interaction. Integrating a touch function into a Liquid Crystal Display (LCD) or Organic Light-Emitting Diode (OLED) display has becoming a research focus to more and more flat panel display manufactures.
In order to further reduce the volume of a touch screen to reduce the size of a mobile terminal with the touch screen, an in cell Touch display Panel (in cell TP) has been developed in the field of display technology in recent years. In the in cell TP, a touch electrode is integrated into a liquid crystal cell. Therefore, a touch screen in which the in cell TP is adopted may have a smaller size than a touch screen in which a One Glass Solution (OGS) is adopted.
Reference is made to FIG. 1, which is a schematic diagram of an in cell TP in related art. A common electrode is arranged above an array substrate 10 of a liquid crystal display panel, for providing a common potential to a pixel unit (not shown). In order to integrate a touch function into the liquid crystal display panel, the common electrode is divided into multiple touch electrode units 12 which are independent from each other, and each touch electrode unit 12 is connected to a touch display chip 11 arranged above the array substrate 10 through a touch electrode lead 13. The working time of the liquid crystal display panel includes a display phase and a touch sensing phase. In the display phase, the touch display chip 11 transmits a touch sensing signal to each touch electrode unit 12; and in the touch sensing phase, the touch display chip 11 transmits a same common signal to all touch electrode units 12.
Reference is made to FIG. 1 again. In the in cell TP, since the touch electrode unit 12 is used to provide the common signal to the pixel unit to display an image, a space between adjacent touch electrode units 12 is generally arranged in a non-display region outside the pixel units. A data line 15 is arranged in a non-display region between adjacent touch electrode units 12 in a horizontal direction (a direction as shown by line AA′).
FIG. 2 is a cross-sectional view along a line BB′ in FIG. 1. A pixel electrode 14 of the pixel unit is arranged below the touch electrode unit 12. An edge electric field is formed between the touch electrode unit 12 and the pixel electrode 14, and drives liquid crystal molecules to rotate. That is to say, the array substrate shown in FIGS. 1 and 2 is an array substrate of a liquid crystal display panel in a Fringe Field Switching (FFS) mode. Referring to FIGS. 1 and 2, the space between adjacent touch electrode units 12 in the horizontal direction (the direction as shown by line AA′) is above the data line 15. When the data line 15 is loaded with a drive potential, a lateral electric field may be generated between the data line 15 and a touch electrode unit 12 loaded with a common potential, so that liquid crystal molecules in a non-display region corresponding to the data line 15 rotate, and a light leakage occurs in pixel units on two sides of the non-display region. In order to reduce the light leakage, in the conventional art, a touch electrode lead 13 is generally arranged above the data line 15 to shield the lateral electric field between the data line 15 and the touch electrode unit 12. However, the light leakage still exists since a position deviation is prone to occur between the touch electrode unit 13 and the touch electrode unit 12 during the manufacture.